The Design Of Aided-Flight Light Constant Current Regulator Based On DSP

Aided-flight light system is a necessary navigation aid facility that ensures the airplanes to take off and land normally during the night or lower visibility circumstance. Its working state, reliability and quality of emergency is closely related with the safety of the airplane's take off - landing and skipping. Airport flight light system is comprised of constant current regulator that as a electrical supplied source,isolation transformer and lamps. At present, the dimmers also use SCR voltage regulating technology in domestic, which output chopped off sine wave directly. Because the speciality of SCR, it causes the deformity of output sine waves, meanwhile the output waves contain lots of high subharmonic, which speed the damage velocity of the cable and the transformer in the light system, disturb the telecommunication in equipments of the light system surround, lower the reliability of the airport system, and bring pollution to electrical network. It is necessary to give up the phase controls and apply high frequency modulate technology to solve electric power pollution.Firstly, the paper introduces the structure and foundation of aided-flight light system, then, it introduces the seedtimes of constant current regulator, airport's mainly applied products currently. Meanwhile it also points out existent defects, and makes a plan that uses the electronic switch IGBT to replace the SCR and applies AC chopping voltage regulator technology to design constant current regulator. This paper chooses the total digital control based on DSP method, combines high frequency PWM pulse width modulation signal, the current degenerative feedback, digital PI control to carries out constant current .The whole system is divided into three fractions: AC voltage regulator main circuit; the DSP hardware platform and weak electricity fraction; software fraction. The three fractions coordinate with each other. According to the procedure setting, the DSP hardware platform sends 20kHz PWM signal, it is sent to logic control circuit. According to logic control request, the main control system does some logic operations, then sends four control signals to drive circuits to control the operation of IGBT. The system program is compiled by MMB software. Its main aim is to complete the function ,such as soft startup, sample current and calculate current warp, digital filter, digital PI automatic control, fault protect, real-time display parameters etc.The constant current regulator which is designed by this topic is based on DSP. The principle of the constant current regulator is explicit, the design is reasonable. It's proved by experiment to be effective for its higher accuracy of constant current, quick protection and veracity. It also be proved that it has a value of matter-of-fact development.